Electrostatographic imaging member and process using anthracene functional polymers

ABSTRACT

Process for preparation of 2-anthryl and substituted 2-anthryl functional monomers and polymers. In the process for preparation of these monomers, an anthracenic reactant of the formula: ##STR1## wherein X and Y are independently selected from hydrogen, chlorine, bromine, alkyl of 1 to 4 carbon atoms or phenyl 
     Is acylated in nitrobenzene under conditions which favor reaction at the two position. The resulting acylated product can then be (a) reacted with an alkylidenephosphorane (Wittig synthesis) or (b) reduced to the corresponding alcohol. Subsequent to such reduction, this alcohol can undergo further modification at the hydroxyl function to form a polymerizable addition monomer. Through the proper selection of the relative concentration of reactants and control over processing conditions, it is possible not only to prepare such monomers in high yields but also upon polymerization of such monomers, to obtain high molecular weight 2-anthryl and substituted 2-anthryl functional polymers (molecular weight of at least 10 4 ). Polymers of such high molecular weight can readily be formed without the use of binders into self-supporting films. Such films are intrinsically photoconductive in the ultraviolet region of the electromagnetic spectrum and have good transport capabilities for charge carriers of both polarities.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a division of application Ser. No. 445,705, filed Feb. 25, 1974now U.S. Pat. No. 3,923,762, which is a continuation-in-part of priorcopending application Ser. No. 417,317, filed Nov. 19, 1973 and nowabandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to processes and products of said processes. Morespecifically, this invention involves a high yield process forpreparation of 2-anthryl and substituted 2-anthryl functional monomers.The monomers resulting from such processes can be polymerized to highmolecular weight (M_(w) ≧10⁴, degree of polymerization ˜40 or greater).These polymers readily form self-supporting films which areintrinsically photoconductive in the ultraviolet region of theelectromagnetic spectrum.

2. Description of the Prior Art

The formation and development of images on the imaging layers ofphotoconductive materials by electrostatic means is well-known. The bestknown of the commercial processes, more commonly known as xerography,involves forming a latent electrostatic image on the imaging layer of animaging member by first uniformly electrostatically charging the surfaceof the imaging layer in the dark and then exposing thiselectrostatically charged surface to a light and shadow image. The lightstruck areas of the imaging layer are thus rendered conductive and theelectrostatic charge selectively dissipated in these irradiated areas.After the photoconductor is exposed, the latent electrostatic image onthis image bearing surface is rendered visible by development with afinely divided colored electroscopic material, known in the art as"toner". This toner will be principally attracted to those areas on theimage bearing surface which retain the electrostatic charge and thusform a visible powder image.

The developed image can then be read or permanently affixed to thephotoconductor where the imaging layer is not to be reused. This latterpractice is usually followed with respect to the binder typephotoconductive films (e.g. zinc oxide pigment in a film forminginsulating resin) where the photoconductive imaging layer is also anintegral part of the finished copy. In so-called "plain paper" copyingsystems, the latent image can be developed on the imaging surface of areusable photoconductor or transferred to another surface, such as asheet of paper, and thereafter developed. When the latent image isdeveloped on the imaging surface of a reusable photoconductor, it issubsequently transferred to another substrate and subsequentlypermanently affixed thereto. Anyone of a variety of well-knowntechniques can be used to permanently affix the toner image to the copysheet, including overcoating with transparent films, and solvent orthermal fusion of the toner particles to this support of substrate.

In the above "plain paper" copying systems, the materials used in thephotoconductive layer should preferably be capable of rapid switchingfrom insulating to conductive to insulating state in order to permitcyclic use of the imaging layer. The increase in the rate of dark decayof the photoconductor. This phenomenon, commonly referred to in the artas "fatigue", has in the past been avoided by the selection ofphotoconductive materials possessing rapid switching capacity. Typicalof the materials suitable for use in such rapidly cycling imaging systeminclude anthracene, sulfur, selenium and mixtures thereof (U.S. Pat. No.2,297,691); selenium being preferred because of its superiorphotosensitivity.

In the past, the use of anthracene in photoconductive insulating layershas been limited exclusively to the inclusion of the crystalline form ofthis material in a binder, since high molecular weight anthracenefunctional polymers have been virtually impossible to prepare. Forexample, attempts to synthesize high molecular weight anthracenepolymers from 9-vinylanthracene by free radical initiated polymerizationtechniques generally yields only oligomers. Attempts at cationicpolymerization of these same monomers yields only low molecular weightmaterials of questionable structure; postulated to be a mixture of lowmolecular weight polymeric materials containing structural units from9-vinylanthracene and 9,10-dimethyleneanthracene. Anionic polymerizationof 9-vinylanthracene also yields only oligomers having a degree ofpolymerization in the range of from about 4 - 12. Attempts tocopolymerize 9-vinylanthracene with other monomers, such as styrene,does not apparently improve the chances of obtaining polymeric productsof high molecular weight. Apparently, resonance stabilization of theanthracene free radical under the conditions prevailing during suchpolymerization, favors formation of a non-propagating radical thuspreventing the further growth of the polymer chain, A. Rembaum et al,Macromol Rev. 1, 57 (1967).

Apparent attempts at preparation of homopolymers of 2-vinylanthraceneand 1-vinylanthracene and styrene copolymers thereof have proven equallyfruitless, yielding only low molecular weight products.

Recently, the synthesis of copolymers of 9-anthrylethyl acrylate andmethyl methacrylate has met with limited success; VysokomolekulyarnyeSoedineniya A14(5): 1127-31 (1972). The anthracene functionality ofthese polymers (generally less than 1%) provides luminescent markers(scintilators) for assistance in the study of the relaxation propertiesand conformation transformation of methyl methacrylate. Other copolymerscontaining anthracene groups have also been synthesized includingpolycondensates, formaldehyde resins, oligoarylenes; however, all ofthese polymeric products have relatively poor mechanical properties andcannot be readily formed into self-supporting films.

It is, therefore, the object of this invention to remove the above aswell as related deficiencies in the prior art system.

More specifically, it is the principle object of this invention toprovide a process for preparation of anthracenic monomers in highyields.

Another object of this invention is to provide anthracenic monomerswhich can be readily polymerized into high molecular weight anthracenicfunctional polymers.

Still another object of this invention is to provide a process forpolymerization of such anthracenic monomers into anthracenic functionalpolymers.

Yet another object of this invention is to provide a high molecularweight scintilating polymer having anthracenic functionality.

It is a further object of this invention to provide an anthracenicfunctional polymer suitable for use in photoconductive imaging membersand methods.

SUMMARY OF THE INVENTION

The above and related objects are achieved by providing a process forpreparation of 2-anthryl and substituted 2-anthryl functional monomersof the formulae ##STR2## wherein R is hydrogen or alkyl of 1 to about 3carbon atoms; and X and Y are independently selected from hydrogen,chlorine, bromine, alkyl of 1 - 4 carbon atoms, or phenyl. -and-##STR3## wherein R₁ is hydrogen or alkyl of 1 -6 carbon atoms; R₂ isalkyl of 1 - 4 carbon atoms; and X and Y are independently selectedhydrogen from chlorine, bromine, alkyl of 1 - 4 carbon atoms, or phenyl

In these processes, a nitrobenzene dispersion containing an anthracenereactant of the formula ##STR4## wherein X and Y are independentlyselected from hydrogen, chlorine, bromine, alkyl of 1 - 4 carbon atomsor phenyl

is contacted with a separate solution containing a complex of anacylating agent and a Lewis Acid at a temperature of from about 5° toabout 50° C for an interval sufficient to effect acylation of at leastsome of the anthracenic reactant at the 2-position. The relative molarratio of acylating agent to Lewis Acid in said separate solution ispreferably 1:3 (in the case of the acylating agent being an acidanhydride) or 1:1 (in the case of the acylating agent being an acid oracid chloride); and the relative molar ratio of acylating agent toanthracenic reactant is preferably 2:1 or slightly greater. The acylatedanthracenic reactant is then further modified at the carbonyl sitewhereby a 2-anthryl or 2 substituted 2-anthryl functional additionmonomer is prepared. The procedures and reactants used in suchmodification will vary with the specific addition monomer desired.

DESCRIPTION OF THE INVENTION INCLUDING PREFERRED EMBODIMENTS

Preliminary to preparations of such monomers, two separate mixtures areprepared; one containing the anthracenic reactant and a secondcontaining a complex of Lewis Acid and acylating agent. The relativemolar ratio of Lewis Acid to acylating agent in such mixtures can rangefrom about 0.5:1 to about 5:1, with best results being obtained whereslightly in excess of an equimolar amount of Lewis Acid is present. Itis essential to maintain a constant ratio of Lewis Acid to acylatingagent in the presence of the anthracenic reactant to reproducibly highyields of acylated product. Typical of the Lewis Acids which can be usedin such second solution include ammonium chloride, aluminum bromide,phosphorous chloride, ferric chloride, stannic chloride, titaniumtetrachloride, boron chloride, zirconium tetra chloride, and sodiumaluminum chloride. Representative of the acylating agents which can besuitably complexed with the above Lewis Acids include acetic acid,acetic anhydride and acetyl chloride.

The relative molar ratio of acylating agent to the anthracenic reactantmust also be carefully adjusted in order to insure that the reactionequilibrium favors the acylation of the anthracenic reactant at the2-position. Good results have been attained where the molar ratio ofacylating agent to anthracenic reactant is in the range of from about1:1 to about 5:1 and preferably about 2:1. It is also advisable to limitthe volume of nitrobenzene in the reaction medium to the minimum amountrequired for dissolving the anthracenic reactant and the LewisAcid/acylating agent. The presence of excessive amounts of nitrobenzenecan result in some loss of acylated product due to problems of isolationof this product from the solvent. It is generally preferred that thevolume of nitrobenzene be limited from about 600 to about 1,500milliliters solvent per 150 grams of anthracenic reactant; this amountinclusive of the amount of nitrobenzene necessary to prepare both thesolution containing the anthracenic reactant and the solution containingthe Lewis Acid/acylating agent complex.

In addition to nitrobenzene by itself, solvent mixtures containingpredominantly nitrobenzene (in excess of 50% by volume) and otherorganic liquids can also be used as the vehicle in which the acylationof the anthracenic reactant takes place. However, as other solvents areintroduced into the reaction medium, the directivity of acylation at the2-position rapidly progressively decreases. Representative of thesolvents which can be used in combination with nitrobenzene as thevehicle for carrying out the acylation of the anthracenic reactantinclude carbon tetrachloride, carbon disulfide and chloroform; and,however, yields of desired product will show an appreciable decline.Subsequent to preparation of separate solutions containing theanthracenic reactant and the Lewis Acid/acylating agent complex, the twosolutions are combined by the gradual addition of the solutioncontaining the Lewis Acid/acylating agent complex to the anthracenicreactant solution over a period of from about 15 minutes to about 60minutes. Upon completion of combination of the two solutions, theingredients contained therein are allowed to react for an additionalperiod of from about 1 to 20 hours. The temperature of this combinedsolution is maintained within a range of from about 5° to about 50° Cand preferably within a range of from about 10° to about 30° C duringthe mixing and the reaction of the ingredients of the two solutions.

It is also advisable, although not critical, to carry out this acylationreaction in an inert non-oxidizing atmosphere. Moreover, because of thephotoactive nature of such anthracenic materials, the reaction massshould also be shielded from activating electromagnetic radiation. Theacylation reaction is terminated by precipitation of an acylatedanthracenic reactant/Lewis Acid complex from the nitrobenzene solutionby the addition of a non-solvent of this complex to the reactionmixture. Solvents which are suitable for precipitation of such materialsincludes benzene, toluene and carbon tetrachloride. The volume ofsolvent used in precipitation of this complex must be carefullycontrolled so as to avoid "oiling out" of the desired product and thusmaking its recovery more difficult. The precipitated complex is thendecomposed with aqueous hydrochloric acid and the product thereafterdried. The acylated product thus obtained, (hereinafter referred to asthe "intermediate") is further purified by recrystallization fromethanol, benzene or other suitable solvents.

The intermediate prepared as described above can now be further modifiedat the carbonyl oxygen by any one of a variety of reactions dependingupon the specific monomer desired. For example, α-alkyl vinyl monomerscorresponding to formula I can be prepared by simply reacting thecarbonyl functional anthracenic reactant with an alkylidenephosphoranein accord with the procedure described by Wittig et al, Ber. 87, 1318(1954) and Ber. 88, 1654 (1955). Alternatively, the above intermediatecan be reduced to the corresponding alcohol by a process involving firstdispersion the intermediate in an appropriate organic solvent, such aslower alkyl alcohols, tetrahydrofuran, ethers or diglyme. To thisdispersion is subsequently adding a reducing agent such as sodiumborohydride, potassium borohydride, lithium aluminum hydride/aluminumchloride, and lithium aluminum hydride/boronfluoride; the boronhydridereducing agents being generally preferred. The relative molarconcentration intermediate to reducing agent should be at least 1:1 andpreferably in excess of equimolar amounts of reducing agent should beused. Upon completion of addition of the reducing agent to theintermediate solution, the resulting mixture is heated to boiling underreflux conditions for about 4 hours and then the reflux condenser openedto permit removal of volatile solvent contained therein residues. Thesolid residues remaining in the reaction vessel upon evaporation of suchsolvents are then allowed to cool to room temperature and thereaftercontacted with aqueous hydrochloric acid for decomposition of residualtraces of reducing agent which may be present in the isolated product.The solid reaction product thus obtained can be separated from thisacidic solution by filtration or extracted with ether and the solidsisolated from the extractant by conventional means.

Monomers corresponding to formula I can be prepared from thisanthracenic alcohol by at least two convenient routes. For example, thealcohol can be initially reacted with a metal halide or acid halide(e.g. thionyl chloride) whereby the hydroxyl group of the alcohol isdisplaced by a halogen atom. Following such displacement, the resultinghalogenated anthracene functional compound is heated in a basic solution(e.g. Li₂ CO₃ in dimethylformamide) for an interval sufficient to causeits dehydrochalogenation and thus formation of the vinyl analogue. Asecond route which can be used in conversion of the alcohol to the vinylmonomer involves simply heating of said alcohol over a paladium catalystfor an interval sufficient to cause its dehydration.

Monomers corresponding to formula II can be prepared from the aboveanthracenic alcohol by condensation of an alpha alkyl acryloyl halidewith said alcohol in a suitable solvent, such as dioxane. It is alsosuggested that a small quantity of triethylamine be present in saidsolution in order to absorb the acid generated as a result of thecondensation of these materials and thus avoid subsequent hydrolysis ofthe desired reaction product once it has formed. In the event that oneor more of the above materials is not readily soluble in the reactionmedium, this medium can be gradually heated until all reactants arecompletely dissolved. It is also recommended that the relativeconcentration of alpha alkyl acryloyl halide to anthracenic alcohol beadequate to achieve substantially complete condensation of the twomaterials. Good results are obtained where equimolar amounts of the tworeactants are present in the solution and preferably where there is aslight molar excess of alpha alkyl acryloyl halide. Following completionof the addition of said reactants to the reaction medium the monomerwill begin to form, as evidenced by the appearance of the precipitate atthe bottom of the reaction vessel. The reaction can be allowed toproceed for up to about 24 hours whereupon it is terminated by theaddition of water to the reaction medium. The addition of water causesincreased precipitation of monomer. Unreacted alpha acryloyl halidedissolves in the water and is thus readily separated from the monomericproduct. Monomer solids can then be recovered from the reaction mediumby filtration, dried and recrystallized from a benzene/hexane solventmixture.

It is both essential and critical that the monomers prepared asdescribed above are isolated in a manner which mminimizes oxidation ofthe anthracene and substituted anthracene functional groups. This can beachieved by carrying out the precipitation, separation andrecrystallization of these monomers under a blanket of inertnonozidizing gas, such as argon or nitrogen. Upon obtaining the desiredmonomeric materials, they are stored either in a vacuum or in an inertnonoxidizing atmosphere. Prior to polymerization of such monomers theyare further purified for the removal of oxidation products. In order tofurther insure that the monomer is devoid of oxidation products of theanthracene and substituted anthracene functional groups, a solution ofthe monomer is passed through a column of activated neutral or basicalumina, the pure monomer collected, and the eluent evaporated therefromunder a vacuum. Such purification procedures must also be carried out ina nonoxidizing atmosphere.

The vinyl monomers (formula I) prepared as described above can bepolymerized in a non-oxidizing atmosphere by a free radical, anionic orcationic polymerization mechanism. Initiator compounds which aresuitable for use in such free radical initiate addition polymerizationsinclude the various peroxides or azobisisobutyronitrile and analogousinitiators. Anionic polymerizationtion of these monomers also yieldshighly satisfactory polymers. It is generally preferred that suchanionic polymerization system be maintained below about 0° C, (in orderto avoid the type of inhibiting processes which commonly occur at highertemperatures), and that such polymerization be initiated with an"addition" type initiator. Cationic polymerization is the leastpreferred of the three systems due to the relatively low molecularweights of the polymers produced thereby.

Acrylate monomers corresponding to formula II can beformed into polymersby standard free radical initiated addition polymerization techniques.Of course, until substantially all of the monomer has been polymerizedthe environment within the reaction vessel should remain substantiallyfree of oxygen. Many of the peroxide initiators traditionally used infree radical polymerization systems have been known to affect hydrogenabstraction of such acrylate polymers, resulting in cross-linking ofthese materials. Therefore, it is generally preferred that free radicalinitiated addition polymerization of these monomer be carried out withazobisisobutyronitrile and analogous initiator materials.

Once having prepared such polymer resins, they are separated from theirrespective polymerization media and dried. These resins can then bereadily dissolved in a number of organic solvents, such astetrahydrofuran, dimethylformamide, toluene, cyclohexanone or theirrespective solvent mixtures, and the resulting solutions sprayed, draw,dipped and/or melt coated on a suitable (preferably conductive)substrate. The ease with which such polymers can be dissolved in theabove organic solvents in one of the unique characteristics of thepolymers prepared by the process of this invention. The amount of suchpolymers which is imparted to the substrate can vary with thecontemplated utility of the film. After applying a coating of thesematerials to the substrate, the resultant film is allowed to dry untilsubstantially free of residual solvent. In the event that the polymersolution is spray coated onto such a substrate, the resulting dry filmmay possess a rough surface texture. Such surface roughness can beeliminated by simply heating this polymer coating sufficiently to causeit to flow.

The quantity of polymer applied to such substrates is carefullymonitored in order to insure that the resulting coating is both coherentand forms a substantially uniform film on the supportive member.Generally, film thickness is controlled in a dip coating application bythe adjustment of the viscosity of the coating solution and/or bycontrol of the temperature and humidity of the post coating environment.In the event that the polymeric layer is prepared by solvent casting ofa polymer solution on a supportive member, mechanical means can also beused in addition to adjustment of viscosity in control the filmthickness of the polymer coating. For example, the use of the doctorblade having a wet gap setting of about 0.005 inches to assist inspreading of the resinous dispersion on a substrate will insure that theresultant film thickness of said coating will not exceed about 15microns. Films prepared from such polymeric materials having a thicknessin the range of from about 0.1 to about 300 microns can be used inconventional electrophotographic imaging members either as the chargecarrier generating element or as an electronically active matrix for thetransport of charge carriers generated by another photoconductivematerial; separation of carrier generation and transport being disclosedin UK Patents 1,337,228 and 1,343,671 which are hereby incorporated byreferenced in their entirety.

Virtually, any of the traditionally employed conductive self-supportingsubstrates used in the preparation of electrophotographic imagingmembers can be operatively associated with such films. Typical of theconductive materials which can be satisfactorily used as the substratesof such imaging members include aluminum; chromium; stainless steel,brass; copper; beryllium copper; their respective alloys; metalizedplastic films, metal coated plastic films (e.g. polyethyleneterephthalate coated with vacuum deposit aluminum); and glass substrateshaving conductive oxide having coatings.

The film prepared from these polymer compositions, as indicatedpreviously are photoconductive in the ultraviolet region of theelectromagnetic spectrum. In order to shift the photoresponsiveness ofsuch materials into the visible region of the spectrum such polymers canbe sensitized by the addition of a dyestuff or an activator (e.g. anelectron donor and/or electron acceptor material). The concentration ofsuch sensitizers within the polymer must be sufficient to extend theabsorption of said materials into the visible range. Generally, anywherefrom about 0.1 to about 10 weight percent of such sensitizers issufficient to achieve such enhancement in spectral response.

It may also be desirable in order to enhance or modify the physicaland/or electrical properties of the polymers of this invention tocopolymerize one or more of the above monomers with a non-anthracenicmonomer. The resulting copolymer will of course vary with the relativereactivity ratio of the monomers present in the charge and the manner inwhich such polymerization is carried out. For example, many of the aboveanthracenic polymer segments may be copolymerized with elastomers inorder to enhance the flexibility of a film of such materials.

The Examples which follow further define, describe and illustrate thevarious processes of this invention and the products produced thereby.Apparatus and techniques used in such processes and evaluation of theirrespective products are standard or as hereinbefore described. Parts andpercentages appearing in such Examples are by weight unless otherwiseindicated.

EXAMPLE I

Into a 5 liter flask containing 150 milliliters nitrobenzene isdispersed about 150 grams (0.84 moles) of anthracene. The flask and itscontents are purged of air with nitrogen and thereafter cooled to about15° C. In a separate flask containing 500 milliliters nitrobenzene isdispersed 255 grams (1.9 moles) of anhydrous aluminum chloride. To thisaluminum chloride solution is slowly added 150 milliliters (1.6 moles)of acetic anhydride. The aluminum chloride solution is vigorouslyagitated during such addition. The aluminum chloride/acetic anhydridecomplex prepared as described above is now combined with the anthracenedispersion by gradual dropwise addition of this complex to theanthracene over a period of approximately one hour. The temperature ofthe resulting mixture is maintained at about 15° subsequent tocompletion of said addition. After 18 hours, the reaction of thesematerials is quenched by the addition of about 1800 milliliters of drybenzene to the combined solution. The reaction mixture is stirred for anadditional 4 hours, the precipitated complex contained therein separatedfrom the liquid by filtration, washed with approximately 200 millilitersbenzene and then washed again with an greater amounts of hexane. Thesolid complex is now hydrolyzed in a dilute acid solution (2%hydrochloric acid), the resulting product separated from the hydrolyzedmedium by filtration, washed to neutral reaction with water, dried andrecrystallized from a benzene/hexane solution after charcoal treatment.The product thus obtained, 2-anthrylmethyl ketone, is a yellow-greenpowder, M.P. 188° C. Yield: 98 grams.

EXAMPLE II

In order to demonstrate the criticality of formation of the complexbetween the Lewis Acid and the acylating agent prior to admixture withanthracene, the procedures of Example I are repeated except for theseparate addition of acetic anhydride and aluminum chloride to theanthracene dispersion.

About 150 grams of anthracene is dispersed in a reaction vesselcontaining 200 milliliters nitrobenzene and 150 milliliters aceticanhydride. The mixture is cooled to about 15° C and both the vessel andits contents purged of air with nitrogen. In a separate flask, 255 gramsof anhydrous aluminum chloride is dissolved in 500 milliliters ofnitrobenzene. This aluminum chloride solution is added by dropwiseaddition to the vessel containing the anthracene/ acetic anhydridemixture. During such addition the contents of the reaction vessel aremaintained in a constant state of agitation. Upon completion of additionof the aluminum chloride solution to the reaction vessel, the contentsof said vessel are stirred for an additional 18 hours at 15° C. Thecomplex formed by the reaction of the material within the reactionvessel is precipitated from solution by the addition thereto of 1800milliliters of dry benzene. After 4 hours, the precipitation of thecomplex is complete and it is separated from the reaction medium byfiltration, dried and recrystallized from a benzene/hexane solutionafter charcoal treatment. M. P. 187°- 188° C. Yield: 8 grams.

It is evident that the separate addition of the Lewis Acid and theacylating agent to the anthracenic reactant dramatically reduces theyield of the intended product.

EXAMPLE III

The procedures of Example II are repeated with identical amounts ofreactants under identical conditions. The product obtained has a meltingpoint of 187° - 188° C. Yield: 35 grams.

EXAMPLE IV

Example II is repeated with identical amounts of reactants underidentical conditions. The melting point of the product thus obtained is187° - 188° C. Yield: less than 1 gram.

Comparison of the results of Example II, III and IV indicate that wherethe Lewis Acid and acylating agent are separately added to theanthracenic reactant, reproducibility of the reaction, especially withregard to yeild of desired product, is purely a matter of chance.

EXAMPLE V

The procedure of Example II is substantially repeated except for thesubstitution of benzene for nitrobenzene as the reaction vehicle.

About 89 grams (0.5 moles) of anthracene is dispersed in a reactionvessel containing 500 milliliters benzene and 113 milliliters (1.5moles) of acetyl chloride. 200 grams of anhydrous aluminum chloride isadded to the reaction vessel in small increments over a period of onehour. The resulting mixture is stirred in an ice bath for about 90minutes and the temperature thereafter allowed to rise to about 25° C.The contents of the reaction vessel is stirred for an additional 18hours, the reaction of materials contained therein quenched by theaddition of ice water, the reaction product extracted with benzene,washed with water and dried. Benzene remaining in the product evaporatesduring drying however, acetophenone residues remaining in the productare removed in vacuo. The product thus obtained is recrystallized (x2)from heptane/benzene mixtures (10:1) with charcoal treatment and thenagain from ethanol (x2). Yield 5 grams of 2 - anthryl methyl ketone,M.P. 185° - 186° C.

It is evident that the substitution of benzene for nitrobenzene ofExample II also results in yields substantially less than thatobtainable by Example I and further introduces impurities within thedesired product requiring separate removal.

EXAMPLE VI

The procedure of Example I is repeated except for a shift in therelative concentration of aluminum chloride from 255 grams to about 127grams. Yield: 27.5 grams of 2-anthryl methyl ketone, M.P. 187° C.

It is evident from this Example that the relative concentration ofaluminum chloride is critical in yield of the desired product snce a 50%reduction in aluminum chloride results in approximately a 75% reductionin the desired product.

EXAMPLE VII

The procedures of Example I are repeated except for a shift in therelative concentration of acetic anhydride used in the acylating complexfrom 155 milliliters to 80 milliliters. Yield: 45 grams of 2-anthrylmethyl ketone, M.P 187° - 188° C.

It is evident from this Example that the yield of product isapproximately directly proportional to the concentration of aceticanhydride used in formation of the acylating agent complex.

EXAMPLE VIII

About 53 grams of the product of Example I is added to a 3 liter flaskcontaining 1800 milliliters ethanol, the reaction vessel and itscontents purged of air with nitrogen, heated to boiling under refluxconditions and 25 grams of sodium borohydride in 280 milliliters ofwater slowly added thereto. The mixture becomes increasingly homogenouswhen about 2/3 of the total borohydride solution has been added. Thesolution is heated to boiling under reflux for about 2 hours, its volumereduced by about 1/3 by evaporation of some of the ethanol and theproduct contained therein isolated by precipitation with a slightlyacidic aqueous solution. The precipitated product is separated from thereaction vehicle by filtration, washed with water, dried andrecrystallized from benzene with charcoal treatment. Yield: 50 grams ofalpha-(2-anthryl) ethanol, M.P. 164° C.

About 50 grams of alpha-(2-anthryl) ethanol is dissolved in 600milliliters of anhydrous benzene and heated to boiling under refluxconditions. To this boiling solution is then added 20 milliliters ofthionyl chloride. The addition of the thionyl chloride to the alcoholsolution proceeds very gradually in the beginning and then more rapidlyas the reaction between these materials begins to take place. Subsequentto the addition of the thionyl chloride, the reaction vessel is purgedwith nitrogen and the contents of the flask heated under this nitrogenblanket for an additional three hours, allowed to cool to roomtemperature and poured into about 1.2 liters of petroleum ether. Theproduct thus obtained is separated from the ether by filtration, washedwith additional amounts of petroleum ether and recrystallized from abenzene/hexane solution. Yield: 46 grams of light green powder,alpha-(2-anthryl) chloroethane, M.P. 170 to 178 (with decomposition).

About 45 grams of alpha-(2-anthryl) chloroethane is added to 350milliliters of dimethylformamide containing 25 grams of lithiumcarbonate. The reaction vessel containing this mixture is purged of airwith nitrogen, heated to 130° C and maintained at this temperature for aperiod of about 4 hours. The contents of the reaction vessel are thenpoured into a very dilute solution of aqueous hydrochloric acid. Theproduct thus obtained is separated from the acidic medium by filtration,dried, recrystallized three times from benzene/hexane solutions aftertreatment with charcoal. Yield: 30 grams of a yellow powder,2-vinylanthracene, M.P. 210° C.

Subsequent to its preparation the 2-vinylanthracene is recrystallized atleast one more time from benzene/hexane solution, dissolved in adegassed benzene/hexane mixture and passed through a column of basicalumina which has been shielded from light. The monomer is eluted withdegassed benzene, the eluent being collected in a light tight ampuleunder an argon blanket. The shielded ampule containing the purifiedmonomer is then attached to a vacuum line, the solvent evaporatedtherefrom and the ampule sealed. The monomer can be stored without anyadverse effects provided it is shielded from light (especiallyultraviolet light).

The monomer in the ampule (approximately 1 gram) can be polymerized bystandard free radical initiated addition polymerization techniques bysimply injecting a solution comprising 8 milliliters of xylene (whichhas been previously purified by passage through a column of activatedalumina and subsequently degassed) and 0.05 milliliters of di-t-butylperoxide through a side-arm of the ampule. Argon gas is used to assistthe infusion of the xylene initiator solution into the ampule. Followinginfusion of the above materials into the ampule, the ampule is insertedinto liquid nitrogen whereupon the solution contained therein freezesand the residual gasses within the ampule removed by a vacuum.Subsequent to removal of gas from the ampule, it is resealed and heatedfor 48 hours at 115° C. The ampule is then opened and the polymerprecipitated with methanol, recovered by the filtration, dried andreprecipitated from a benzene solution with methanol. Yield: 0.97 gramsof poly(2-vinylanthracene), M_(w) = 80,000 as determined by gelpermeation chromotography and light scattering techniques.

EXAMPLE IX

The following Example illustrates the cationic polymerization of amonomer prepared as described in Example VIII. Preliminary to suchpolymerization, 20 milliliters of methylene chloride (having beenpreviously purified by passage through a column of activated alumina anddegassed) is vacuum distilled into a sealed light tight ampulecontaining about 2 grams of 2-vinylanthracene. After the monomer isdissolved, about 1 milliliter of catalyst solution (0.2 millilitersboron trifluoride etherate in 200 milliliters of similarly purifiedmethylene chloride) is also introduced into the ampule, the ampuleresealed and the combined solution heated to about 35° C. After about 48hours of continuous heating or stirring, the polymerization is quenchedand polymer solids precipitated by pouring the contents of the ampuleinto methanol. The precipitated polymer solids are separated from themethanol by filtration and reprecipitated from benzene with methanol.Yield: 0.6 grams of yellow powder, M_(w) = 18,000 (as determined by gelpermeation chromotography).

EXAMPLE X

The procedures of Example IX are repeated except for the preexposure ofthe monomer to air and diffuse roomlight for about one hour prior toattempting its polymerization. The monomer could not be thereafterpolymerized.

EXAMPLE XI

The following Example illustrates the anionic polymerization of amonomer prepared as described in Example VIII. Preliminary to suchpolymerization, 200 milliliters of dried, oxygen free tetrahydrofuran isvacuum distilled into a light tight ampule containing 3 grams of2-vinylanthracene. After the monomer is dissolved, the ampule and itscontents are chilled to -78° C, and about 5 milliliters of initiatorsolution (5 × 10⁻⁵ moles of the sodium salt of alpha methyl styrenetetramer in tetrahydrofuran) injected into the ampule through a side armon the ampule. Polymerization of the monomer proceeds upon thecombination of these two solutions. After 5 days of continuous stirringat -78° C, the contents of the ampule are poured into methanol forprecipitation of the polymer. The polymer solids are then recovered fromthe methanol by filtration and reprecipitated from benzene with methanolfor removal of impurities, monomer residues and low molecular weightfractions. Yield: 3.0 grams of white polymer M_(w) = 1,000,000, M_(w)/Mn 2.87.

EXAMPLE XII

The anionic polymerization of 2-vinylanthracene is repeated according tothe procedures of Example XI with the following modifications: thepolymerization temperature is increased from -78° C to -32° C andreaction time extended from 5 days to 20 days. Yield: 3.0 grams of whitepolymer M_(w) = 2,890,000 M_(w) /Mn 10.1.

EXAMPLE XIII

The anionic polymerization of 2-vinylanthracene is repeated according tothe procedures of Example XI with the following modifications: prior toinitiation of polymerization, the monomer is exposed to air and diffuseroomlight for one hour. The monomer cannot thereafter be polymerized.

EXAMPLE XIV

Preparation of 2-(2-anthryl) propene -- Into a 500 milliliter flaskwhich has been purged of air with nitrogen are placed 16.6 grams oftriphenylmethylphosphoniumbromide and 100 milliliters oftetrahydrofuran. After the contents of the flask are in solution, theflask is chilled to 0° C, and 21 milliliter of butryl lithium solution(2.2 moles/liter of hexane) also introduced into the flask. The combinedsolution is stirred at 0° C for 16 hours under nitrogen and then thetemperature of the solution allowed to increase to room temperature(approximately 20° C). About 2 grams of 2-anthryl methyl ketone(prepared according to the procedures described in Example I) in 250milliliters of tetrahydrofuran are now added to the above solution, thecombined solution heated to boiling under reflux conditions, and thevolume of the contents of the flask reduced by about 250 millilitersover a period of 90 minutes through the controlled evaporation oftetrahydrofuran. The darkly colored solution remaining in the flask iscooled to room temperature, poured into an alcoholic solution (50:50ethanol and water) for precipitation of the monomer the monomer solidsseparated from the alcoholic solution by filtration, dried andreprecipitated from hexane/heptane mixtures. Yield: 8.8 grams of crudemonomer. The monomer is further purified according to the proceduresdescribed in Example VIII. The resulting monomer, 2-(2-anthryl) propane,is a white powder, MP = 153° C.

About 100 milliliters of tetrahydrofuran is vacuum distilled into alight tight ampule containing the above monomer, the ampule chilled tothe temperature of dry ice (approximately -40° C) and about 5milliliters of initiator solution (5 × 10⁻⁵ moles of the sodium salt ofalphamethyl styrene tetramer in tetrahydrofuran) injected into theampule through a side arm on the ampule. Polymerization of the monomercommences upon the introduction of the initiator into the ampule. Afterabout 24 hours of continuous stirring at -40° C, the contents of theampule are emptied into a flask containing methanol thereby quenchingthe polymerization reaction and precipitating the polymer. The polymersolids are recovered from the methanol solution by filtration, dried andreprecipitated from benzene with methanol. Yield: 8.0 grams of whitepolymer, M_(w) 280,000, M_(w) /Mn 1.74.

EXAMPLE XV

Preparation of poly(1(2-anthryl)-ethyl methacrylate) -- About 0.84 moles(150 grams) of anthracene is dispersed in 150 milliliters nitrobenzene.This dispersion is prepared in a reaction vessel equipped with anaddition funnel, a thermometer, a source of non-oxidizing gas and amagnetic stirring bar. The dispersion is chilled to about 15° C. In aseparate container about 1.9 moles (255 grams) of aluminum chloride isdissolved in 480 milliliters nitrobenzene. About 1.6 moles (155milliliters) acetic anhydride is added to the aluminum chloride solutionby dropwise addition. The aluminum chloride solution is rapidly agitatedduring such addition. The temperature of this solution is carefullymonitored since the formation of the complex between the aluminumchloride and the acetic anhydride is strongly exothermic. Subsequent toformation of this complex, it is transferred to the addition funnel. Thereaction vessel containing the anthracene dispersion is vigorouslyagitated and the aluminum chloride/acetic anhydride complex addeddropwise over a period of about 60 minutes. The temperature of theanthracene dispersion is maintained at 15° during the addition of thiscomplex. About 5 hours after completion of addition of the complex tothe anthracene dispersion, the reaction of these materials is quenchedby the addition of 1500 milliliters of cold, dry benzene (cooled to ˜8°C) The reaction vessel is chilled in an ice bath after the addition ofbenzene and maintained at this temperature for approximately 4 hours.The red solids formed during this reaction are separated from thereaction mass by filtration, washed with additional amounts of drybenzene and hexane for removal of nitrobenzene residues from the solids.The filtration and subsequent washing of the recovered solids should beperformed in a low humidity environment in order to prevent prematurehydrolysis of the recovered solid product. Subsequent to removal ofresidual traces of nitrobenzene from this product, it is hydrolyzed inan aqueous solution of hydrochloric acid (200 milliliters ofconcentrated HCl per 2 liters distilled water). The solids are thenrecovered by filtration, washed continuously with distilled water untilall traces of acidity are removed, dried in a vacuum oven and purifiedby recrystallization from a benzene/hexane (1:1) solvent mixture. Therecovered product, 2-acetyl-anthracene, is light-green in appearance.Yield: 98 grams, MP 188° C.

About 53 grams of 2-acetyl anthracene is dispersed in 1800 millilitersof ethanol, the dispersion heated to boiling under reflux conditions and25 grams of sodium borohydride in 280 milliliters distilled water addedby dropwise addition. During the addition of the sodium borohydride, thedispersion is maintained in a constant state of mild agitation. With theaddition of about two-thirds of the sodium borohydride solution, thedispersed matter dissolves in the solvent and turns brown in color. Uponcompletion of addition of the sodium borohydride, the resulting solutionis heated under reflux conditions for an additional two hours. At thistime, the reflux condensor is opened and approximately 2/3 of thevolatile solvents contained within the mixture allowed to escape. Theproduct remaining in the reaction vessel is isolated from excess sodiumborohydride by hydrolysis with an aqueous solution of hydrochloric acid(200 milliliters HCl per two liters of distilled water). Uponprecipitation of the isolated product, it is filtered, washed withalternate solutions of aqueous hydrochloric acid and distilled water,dried and recrystallized from benzene. The recovered product,1-(2-anthryl) ethanol, is white in color. Yield: 50 grams, M.P. 164° C.

About 50 grams of 1-(2-anthryl) ethanol is dissolved in 375 millilitersof dioxane. To this solution is subsequently added 37.5 milliliters oftriethylamine and 27.5 milliliters methacryloyl chloride. Thecondensation of the 1-(2-anthryl) ethanol and methacryloyl chloride isallowed to proceed for about 24 hours. After that time, the reactionbetween the 1-(2-anthryl) ethanol and methacryloyl chloride is quenchedby the addition of water to the reaction medium. Sufficient water isadded to extract unreacted methacryloyl chloride from the reaction mass.The precipitate which forms is separated from the reaction medium byfiltration, dried in a vacuum oven and recrystallized from a mixedsolvent of benzene and methanol.

About 25 grams of monomer and about 0.05 grams azobisisobutyronitrile (5milliliters of a solution of 0.5 grams azobisisobutyronitrile in 50milliliters benzene) are charged to a light tight resin kettlecontaining 300 milliliters dried benzene. The reaction vessel is purgedwith nitrogen and its contents heated under mild agitation to 60° C andmaintained at that temperature for 24 hours. The polymer is isolatedfrom the reaction mass by precipitation with methanol and precipitatedsolids separated by filtration, washed with methanol and dried. Therecovered solids are further purified by reprecipitation in acetone forremoval of low molecular weight polymer fractions and unpolymerizedmonomer residues. Yield 26 grams, M_(w) 280,000 -- as determined bystandard light scattering techniques (Brice Phoenix Light ScatteringPhotometer).

The polymer thus prepared can now be dissolved in tetrahydrofuran andthe resulting solution spray coated on a suitable conductive substrate.In order to remedy any irregularities in surface texture of such film,the coated substrate is placed on a hot plate and gradually heated in anon-oxidizing environment until it (the coating) begins to flow and thusany surface irregularities eliminated. The dry film thickness of theanthracene functional polymer coating thus prepared is in a range ofabout 15 microns. The resulting plate is evaluated in a standard XeroxModel D copier. Initial copies prepared from this plate have good soliddensity development and good resolution.

EXAMPLE XVI

A film of the polymer of Example XV is spray coated on a smooth TeflonSubstrate. The coated Teflon substrate is heated sufficiently in anon-oxidizing environment to cause the polymer to flow together and thuseliminate any irregularities in the surface of the polymer coating.Sufficient polymer is sprayed onto the Teflon substrate to provide apolymer film thickness of approximately 50 microns. Subsequent tocooling of the polymer film the substrate bearing said film is placed inan evaporator and a photoconductive layer of amorphous seleniumdeposited on the surface of the polymer film. Sufficient selenium isdeposited to form a photogenerator layer having a thickness ofapproximately 1 micron. The coated substrate is transferred to a secondevaporator and a layer of aluminum 15 microns thick vacuum deposited onthe surface of the selenium layer. The coated substrate is removed fromthe evaporator and the polymer/selenium/aluminum composite stripped fromthe Teflon surface of the substrate. This composite is then laminated toa conductive metal platen). (aluminum layer contiguous with the surfaceof said platen). The electrophotographic properties of the composite arenow evaluated on a Xerox Model D copier. Such evaluation comprisesinitially charging the polymer surface of the composite in the dark to apositive potential of about 600 volts, followed by projection of imageinformation on said surface. The source of illumination of the imageinformation is white light. The resulting latent electrostatic imagethus produced is developed by cascading a mixture of toner and carrierover the surface of the composite bearing the latent electrostaticimage. The developed image is transferred to a sheet of paper andpermanently affixed thereto by thermal fusion. Toner residues areremoved from the image bearing surface of the composite and the copycycle repeated. Copy quality is good and is reproducible.

EXAMPLE XVII

A composite similar to that of Example XVI is prepared by thesubstitution of a vacuum deposited layer of X-metal free phthalocyaninefor selenium. Copy quality is good and is reproducible.

EXAMPLE XVIII

About 45 grams of polymer (prepared as described in Example XV) and 5grams X-metal free phthalocyanine are dispersed in a common solvent andthe resulting solution spray coated on a tin oxide coated glass plate(NESA glass). The polymer coating is heated on the plate until moltenthus eliminating any surface irregularities in said coating. Sufficientpolymer/phthalocyanine is deposited on the plate to form a substantiallyuniform binder layer having a dry film thickness of approximately 50microns. The electrophotographic properties of this plate are evaluatedin a Xerox Model D copier in the manner described in Example XVI. Suchcopies are of good quality and such quality is reproducible.

EXAMPLE XIX

About 30 moles of monomer prepared as described in Example XV arecopolymerized with 70 moles methylmethacrylate. The random copolymerthus produced has substantially the same relative content of monomers asare present in the original charge. Upon separation and purification ofthe resulting copolymer it can be dissolved in tetrahydrofuran and dipor draw coated on an appropriate conductive substrate. Sufficientcopolymer is transferred to the substrate to form a dry film having athickness of about 40 microns. The electrophotographic properties of theimaging member thus prepared is evaluated in a Xerox Model D copier.Initial copy quality is good and such quality is reproducible.

EXAMPLE XX

The procedures of Example XIX are repeated except for the substitutionof lauryl methacrylate monomer for the methylmethacrylate monomer usedin preparation of the copolymer. Evaluation of the films prepared fromthis copolymer reveals performance equivalent to that of Example V.

EXAMPLE XXI - XXVI

The monomer synthsis of Example XV is repeated except for thesubstitution of the following acylating agents for acetic anhydride.

    ______________________________________                                        Example No.       Acylating Agent                                             ______________________________________                                        XXI               formyl chloride                                             XXII              acetyl chloride                                             XXIII             propionyl chloride                                          XXIV              butyryl chloride                                            XXV               valeryl chloride                                            XXVI              caproyl chloride                                            ______________________________________                                    

What is claimed is:
 1. In an electrophotographic imaging membercomprising a conductive substrate, a photoconductive layer covering atleast one surface of said substrate and a charge carrier transportmatrix layer overcoating the photoconductive layer, the improvementcomprisinga charge carrier transport matrix layer comprising ananthracene functional polymer having polymer segments which consistessentially of the addition product of at least one monomer of theformula ##STR5## wherein R is hydrogen or alkyl of 1 to about 3 carbonatoms; and X and Y are independently selected from chlorine, bromine,alkyl of 1 - 4 carbon atoms, or phenylsaid polymer segments having adegree of polymerization of about 40 or greater, aid transport layerhaving a thickness of from about 0.1 to about 300 microns.
 2. In anelectrophotographic imaging member comprising a conductive substrate, aphotoconductive layer covering at least one surface of said substrateand a charge carrier transport matrix layer overcoating thephotoconductive layer, the improvement comprisinga charge carriertransport martrix layer comprising an anthracene functional polymerhaving polymer segments which consist essentially of the additionproduct of at least one monomer of the formula ##STR6## wherein R₁ ishydrogen or alkyl of 1 - 6 carbon atoms; R₂ is alkyl of 1 - 4 carbonatoms; and X and Y are independently selected from chlorine, bromine,alkyl of 1 - 4 carbon atoms, or phenylsaid polymer segment having adegree of polymerization of about 40 or greater, said transport layerhaving a thickness of from about 0.1 to about 300 microns.
 3. In anelectrophotographic imaging member comprising a conductive substrate,and a photoconductive insulating layer having a thickness of from about0.1 to about 300 microns wherein a photoconductor material is dispersedin a charge carrier transport matrix, the improvement comprisinga chargecarrier transport matrix comprising anthracene functional polymer havingpolymer segments which consist essentially of the addition product of atleast one monomer of the formula ##STR7## wherein R is hydrogen or alkylof 1 to about 3 carbon atoms; and X and Y are independently selectedfrom chlorine, bromine, alkyl of 1 - 4 carbon atoms, or phenylsaidpolymer segments having a degree of polmerization of about 40 orgreater.
 4. In an electrophotographic imaging member comprising aconductive substrate and a photoconductive insulating layer having athickness of from about 0.1 to about 300 microns wherein aphotoconductive material is dispersed in a charge carrier transportmatrix, the improvement comprisinga charge carrier transport matrixcomprising anthracene functional polymer having polymer segments whichconsist essentially of the addition product of at least one monomer ofthe formula ##STR8## wherein R₁ is hydrogen or alkyl of 1 - 6 carbonatoms; R₂ is alkyl of 1 - 4 carbon atoms; and X and Y are independentlyselected from chlorine, bromine, alkyl of 1 - 4 carbon atoms, orphenylsaid polymer segment having a degree of polymerization of about 40or greater.
 5. An electrostatographic imaging process, comprising:a.providing an electrophotographic imaging member having a conductivesubstrate and a polymeric photoconductive insulating layer having athickness of from about 0.1 to about 300 microns operatively disposed inrelation thereto, said photoconductive insulating layer comprising ananthracene functional polymer having polymer segments which consistessentially of the additional product of at least one monomer of theformula ##STR9## wherein R is hydrogen or alkyl of 1 to about 3 carbonatoms; and X and Y are independently selected from chlorine, bromine,alkyl of 1 - 4 carbon atoms, or phenylsaid polymer segment having adegree of polymerization of about 40 or greater; and b. forming a latentelectrostatic image on the surface of the photoconductive insulatinglayer.
 6. An electrostatic imaging process comprising:a. providing anelectrophotographic imaging member having a conductive substrate and apolymeric photoconductive insulating layer having a thickness of fromabout 0.1 to about 300 microns operatively disposed in relation thereto,said photoconductive insulating layer comprising an anthracenefunctional polymer having polymer segments which consist essentially ofthe additon product of at least one monomer of the formula ##STR10##wherein R₁ is hydrogen or alkyl of 1 - 6 carbon atoms; R_(z) is alkyl of1 - 4 carbon atoms; and X and Y are independently selected from chlorinebromine, alkyl of 1 - 4 carbon atoms, or phenylsaid polymer segmentshaving a degree of polymerization of about 40 or greater; and b. forminga latent electrostatic image on the surface of the photoconductiveinsulating layer.